The idea of the diagonal as used in architecture and visual arts is exemplified in the context of a sound installation in an art gallery. The ideas of local and external sound movement as related to the diagonals in a room and the acoustical coupling of rooms are introduced for a particular location. The implementation of the installation is described according to the type of sound material chosen and its role in space, following the main ideas of diagonals and movements inside and across rooms. Concluding remarks are related to the possibilities of combining sonic and architectural concepts for a sound installation and to the possible implementation of the ideas of this installation in other spaces and with other types of sounds.